ATSAM3U-EK Atmel, ATSAM3U-EK Datasheet - Page 359

• Manufacturer Part Number: ATSAM3U-EK
• Description: KIT EVAL FOR AT91SAM3U CORTEX
• Manufacturer: Atmel
• Type: MCUr

Specifications of ATSAM3U-EK

• Contents: Board
• Processor To Be Evaluated: SAM3U
• Data Bus Width: 32 bit
• Interface Type: RS-232, USB
• Operating Supply Voltage: 3 V
• Silicon Manufacturer: Atmel
• Core Architecture: ARM
• Core Sub-architecture: Cortex - M3
• Silicon Core Number: SAM3U4E
• Silicon Family Name: SAM3U
• Kit Contents: Board CD Docs
• Rohs Compliant: Yes
• For Use With/related Products: AT91SAM3U
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

25.9.2.2
Figure 25-6. Connection of 2 x 8-bit Devices on a 16-bit Bus: Byte Write Option
25.9.2.3
6430D–ATARM–25-Mar-11
6430D–ATARM–25-Mar-11
Signal Multiplexing
Byte Select Access
In this mode, read/write operations can be enabled/disabled at byte level. One byte-select line
per byte of the data bus is provided. One NRD and one NWE signal control read and write.
Depending on the byte access type (BAT), only the write signals or the byte select signals are
used. To save IOs at the external bus interface, control signals at the SMC interface are multi-
plexed.
access type.
For 16-bit devices, bit A0 of address is unused. When Byte Select Option is selected, NWR1 is
unused. When Byte Write option is selected, NBS0 is unused.
Table 25-5.
Signal Name
Device Type
Byte Access Type (BAT)
NBS0_A0
NWE_NWR0
NBS1_NWR1
A1
• For 16-bit devices: the SMC provides NBS0 and NBS1 selection signals for respectively
byte0 (lower byte) and byte1 (upper byte) of a 16-bit bus.
Byte Select Access is used to connect one 16-bit device.
SMC
Table 25-5
D[15:8]
NCS[3]
A[24:2]
SMC Multiplexed Signal Translation
NWR0
NWR1
D[7:0]
NRD
A1
shows signal multiplexing depending on the data bus width and the byte
Byte Select
1x16-bit
NBS0
NBS1
NWE
A1
16-bit Bus
A[23:1]
A[0]
Write Enable
Read Enable
Memory Enable
D[15:8]
A[23:1]
Write Enable
Read Enable
Memory Enable
D[7:0]
A[0]
Byte Write
2 x 8-bit
NWR0
NWR1
A1
SAM3U Series
SAM3U Series
8-bit Bus
1 x 8-bit
NWE
A0
A1
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